Project description:Ocean acidification is recognized as one of the most pervasive anthropogenic impact on marine life. A variety of responses have been highlighted in different marine organisms ranging from physiology to gene and protein expression. However, most of these studies have been performed in laboratory exposing adults or developmental stages to CO2 enriched seawater. To what extend the information obtained from these in vitro experiments may be extrapolated to a natural environment is questionable. Here, we utilized the Castello volcanic CO2 vents at Ischia as natural laboratory to study the P. lividus population living at the low pH zone (pH~7.8) compared to those of sea urchins living at control sites. Wide-ranging analyses were performed in animals collected at the acidified site, including the monitoring of their position, the determination of the physico-chemical parameters of the coelomic fluid and an in depth characterization of coelomocytes regarding the number and type of cells, Hsp70 expression, redox status and protein expression through de-novo sequencing analyses. In addition, the respiration, nitrogen metabolism, and skeletal mineralogy of urchins from the vent were examined in comparison with those from control animals. Overall these analyses allowed to understand how the sea urchins can thrive in low pH/high CO2.
Project description:The available energy and carbon sources for prokaryotes in the deep ocean remain still largely enigmatic. Reduced sulfur compounds, such as thiosulfate, are a potential energy source for both auto- and heterotrophic marine prokaryotes. Shipboard experiments performed in the North Atlantic using Labrador Sea Water (~2000 m depth) amended with thiosulfate led to an enhanced prokaryotic dissolved inorganic carbon (DIC) fixation.
Project description:Vibrio species represent one of the most diverse genera of marine bacteria known for their ubiquitous presence in natural aquatic systems. Several members of this genus including Vibrio harveyi are receiving increasing attention lately because they are becoming a source of health problems, especially for some marine organisms widely used in sea food industry. To learn about adaptation changes triggered by V. harveyi during its long-term persistence at elevated temperatures, we studied adaptation of this marine bacterium in sea water microcosms at 30 oC that closely mimicks the upper limits of sea surface temperatures recorded around the globe.
Project description:In the seabed, chemical defences mediate inter- and intraspecific interactions and may determine organisms’ success, shaping the diversity and function of benthic communities. Sponges represent a prominent example of chemically-defended marine organisms with great ecological success. The ecological factors controlling the production of their defensive compounds and the evolutionary forces that select for these defences remain little understood. Each sponge species produces a specific and diverse chemical arsenal with fish-deterrent, antifouling and antimicrobial properties. However, some small animals (mesograzers), mainly sea slugs, have specialized in living and feeding on sponges. Feeding on chemically-defended organisms provides a strategy to avoid predators, albeit the poor nutritional value of sponges. In order to investigate the mechanisms that control sponge chemical defence, with particular focus on the response to specialist grazers, we investigated the interaction between the sponge Aplysina aerophoba and the sea slug Tylodina perversa. Here we performed controlled experiments and collected sponge samples at different time points (3h, 1d and 6d after treatment). To further elucidate if the sponge response is specific to grazing by T. perversa, we also included a treatment in which sponges were mechanically damaged with a scalpel. We compared gene expression between treatments based on RNA-Seq data.
